The present invention relates to control of the flow of fluids with a hydraulic valve including a flexible portion, such as including a membrane or bladder, through a conduit such as a pipe, culvert, channel, drainage, stream or similar closed or open fluid carrying system.
Prior art fluid flow control devices have typically relied on motor or air-driven valves, slide gate mechanisms or inflatable dams. All of these techniques require external power and/or moving parts subject to problems such as ice formation, dirt and sediment accumulation and/or power failures.
Accordingly, there is a need for a fluid flow control device and method with powerless automation, increased reliability and fewer mechanical parts.